Inspection system for use in monitoring plants in plant growth areas

ABSTRACT

An inspection system is presented for use in monitoring plants&#39; conditions in a plant growing area. The inspection system comprises: an optical probe comprising at least one imaging set, each imaging set comprising: a flash illuminator unit; an imaging unit configured with a predetermined resolution; and a sensing unit; the optical probe being configured and operable to perform one or more imaging sessions on a target in a plant growing area at a target location during a movement of the optical probe along a movement path in a vicinity of the target location, said sensing unit comprising a distance sensing element configured and operable to determine an instantaneous distance between the imaging unit and the target being imaged, and generate distance sensing data indicative thereof; and a control unit configured and operable to be responsive to the distance sensing data to initiate the imaging session and synchronize operation of the flash illuminator unit and the imaging unit to capture images of the target by the optical probe, thereby enabling analyzing the images and determining a condition of the target being indicative of at least one of pest, insect and disease presence at the target.

TECHNOLOGICAL FIELD

The invention relates generally to the agricultural field, and morespecifically to automated systems and methods of monitoring of plantsand/or plant treatment decision making in plant growth areas.

BACKGROUND

Crops require a lot of care, either when grown in protected environment(such as in a greenhouse) or outdoors, especially when cultivated on alarge scale where farmers continuously face a variety of challenges,including the need to maintain plants' health over the whole plant lifecycle, control flower pollination, and insure healthy as well as goodyield crops. Indeed, it can be a difficult task to know whether thecrop, at a specific time point, suffers from a problem, such asexistence of pest, disease, or nutritional deficit, and what is theextent of the problem until it is readily visible. Often by that stage,it may require expensive and extensive intervention. Crop yield isaffected by the physiological performance of the crop throughout itsdevelopment cycle. Precise intervention at critical developmentalstages, allows farmers to achieve high yields of the crop. A commonpractice for monitoring crops for pests, diseases and other deleteriousconditions, has been the use of human scouts who visually inspect thecrop. However, human inspection might take a long time, especially inlarge plant areas, and might facilitate the spread of those pests anddiseases, for example, through physical contact with multiple plants,and is subject to subjective interpretation of the inspecting person.

Many crop management practices are employed based on past practices andoutcome. A common underlying assumption is that crops are uniform andperform evenly which is not necessarily the case.

Sensor systems have been developed for crop monitoring. For example,some systems use a grid of sensors suspended above the crop or which flyover the crops. Handheld devices are also used to capture data fromindividual plants. Other systems rely on visual detection by means ofmotion detection or visual pattern recognition.

Some sensor systems are directed toward specific indicators (presence ofdisease, emergence of pests, etc.) with narrow spectra of responses. Forexample, fluorescent measurement systems have been used to detect farred spectra produced by plants when exposed to blue or red light.Conventional fluorescent measurement requires complex equipment, andtypically a single assessment takes several minutes. Other sensorysystems can collect very general information (temperature, humidity)that cannot accurately pinpoint problems at the level of individualplants.

General Description

The present invention provides novel systems and methods for use intarget inspection applications, which is particularly useful formanagement of crops, for example in greenhouses or open fields (herein,plant growth/growing areas). The technique of the invention enables highquality, yet cost effective and time saving, monitoring and managementof plant conditions, either manually or autonomously, by utilizing noveltechniques for collecting high-resolution characterization data fromeach plant, plant part or portion of the plant part in a crop area, andindividually characterizing and determining the status of each plant,plant part of portion of the plant part, such as existence of disease,pest infestations and detrimental conditions, as well as the growingstage such as flowering and fruitage.

The invention also enables performing analysis of the plant conditionand generating corresponding relevant recommendations for interventions.While being capable of managing each individual plant, the invention isparticularly useful in managing large/multiple farming areas due to thehighly effective data collection and analysis techniques.

The invention provides an inspection system for use in monitoringplants' conditions in a plant growing area. The inspection systemcomprises an optical probe and a control unit. The optical probecomprises at least one imaging set, each imaging set comprising: a flashilluminator unit; an imaging unit configured with a predeterminedresolution; and a sensing unit; the optical probe being configured andoperable to perform one or more imaging sessions on a target in a plantgrowing area at a target location during a movement of the optical probealong a movement path in a vicinity of the target location, said sensingunit comprising a distance sensing element configured and operable todetermine an instantaneous distance between the imaging unit and thetarget being imaged, and generate distance sensing data indicativethereof. The control unit is configured and operable to be responsive tothe distance sensing data to initiate the imaging session andsynchronize operation of the flash illuminator unit and the imaging unitto capture images of the target by the optical probe, thereby enablinganalyzing the images and determining a condition of the target beingindicative of at least one of pest, insect and disease presence at thetarget.

The resolution of the imaging unit is a substantially high resolution,which is defined by a desirably high magnification of the imaging unit.More specifically, such high resolution can be described as a certainrelatively high ratio between a pixel size of an imaging detector and asize of a corresponding smallest region in the object plane which isbeing imaged/projected on said pixel. Hence, for a given pixel matrix ofan imaging detector and a given distance from the pixel matrix to theobject plane, the higher is the resolution the smaller is the field ofview. For example, an object having 0.5 mm in size may require about30×30 resolved pixels in order to be properly imaged with the desirablyhigh resolution. Therefore an effective resolution of about 17 micronsis required. If an imaging sensor with pixels of 3 microns in size isused, and the resolution of the optics, measured for example byline-spread-function or other relevant parameter, is 1.5 camera pixels,then a magnification of about 1/3.8=(3×1.5)/17 is required from theobject to sensor in order to provide the high-resolution capability.

Thus, the desirably high resolution for the plant imaging andinspection, which can be described by a spatial resolution of theimaging unit in an object plane, is practically in a range of 1-100microns. Hence, that the term “high-resolution” as referred to in thisapplication is in the micron resolution range, specifically concerning afew microns, a few tens of microns or a few hundreds of microns. Thespecific choice potentially depends on the objects of interest, e.g. thespecific pests or beneficial insects, and can therefore be defineddifferently between various applications.

Specifically, high-resolution characterization data collected includesone or more of the following, but is not limited to, leaf images, leafunderside images, flower images, plant crown images, fruit images, andplant branch images. Yet more specifically, the images can be of onlyportions of the above plant parts.

Characterization of the plant condition/status may include one or moreof the following, but is not limited to, detection and/or measurement ofleaf shape, color, discoloring, leaf orientation and linearity, pestinsects, beneficial insects, fungi, insect generated liquid drops, fruitsize, fruit location and height from the ground, fruit orientation,fruit shape and fruit color. In addition, one or more of the followingcan be saved in the system for use upon decision making: irrigation andfertilization data, date of planting, date of last harvest, dates ofpruning and others.

Analysis of the plant condition, based on the high-resolutioncharacterization data, can be carried out and may include one or more ofthe following, but is not limited to, generating information on thegrowing stage, and on the location and severity of detrimentalconditions. The growing stage information may include leaf size, leafcolor and leaf density and distribution; flower density anddistribution; fruit size, fruit color and fruit density anddistribution; branch quantity and density. The detrimental conditionsinformation may include fungus location and severity distribution;insect pest location and severity distribution; leaf deformation andseverity distribution.

Analysis output may be in the form of tabular data, density maps ofparametric data, maps with embedded data such as photographs,recommended treatment maps such as beneficial type and density forspreading and insecticide type and spraying parameters.

Recommendation data based on the analysis of the high-resolutioncharacterization data may include interventions that may relate to oneor more of the following, but is not limited to, insecticide spraying,beneficial spreading, irrigation planning, fertilization planning, fruitpruning, leaf and branch pruning, inspection planning, treatment typefor detrimental condition taking into account presence of beneficialspecies. The recommendations may relate to the whole cultivated area orto local requirements in a subsection of the cultivated area, or to amore than one cultivated area. Interventions/Treatment actions mayinclude insecticide spraying, beneficial biological agent distribution,pruning of leaves and branches, thinning of fruit, and fertilizerspreading.

On one hand, diseases, pests, insects, colorization and other plantconditions can be potentially small in size or have similar propertiesand as such require high resolution data collection techniques, in therange of microns, to effectively analyze the collected data, distinguishand determine the plant condition. On the other hand, collecting highresolution data can be basically slow because there is a need to stop atmultiple locations along the way to be able to capture high resolutionimages, thus lowering data collection efficiency. Yet further, plantsand plant parts can be moving with respect to the data collection module(or vice versa) during data collection, thus causing smearing andreducing image quality. The present invention overcomes all theabove-listed shortcomings by enabling fast and high-quality datacollection of high-resolution images, thereby enabling effectivemonitoring of large plant growth areas in optimal time and with highaccuracy.

The sensing unit used in the optical probe is located at a predetermineddistance before the imaging unit with respect to the movement path ofthe optical probe.

The imaging unit may be configured and operable to acquire a pluralityof images with different focal conditions within a focal range of theimaging unit during said imaging sessions. According to someembodiments, the imaging unit defines a plurality of different imagingchannels having said different focal conditions, said distance sensingdata being indicative of the distance between each of the imagingchannels and the target to be imaged. Alternatively or additionally, theimaging unit may define at least one imaging channel configured with anadaptive focus within said focal range for imaging along said at leastone imaging channel, said distance sensing data being indicative of thedistance between each of said at least one imaging channel and thetarget to be imaged. The control unit may thus comprise an imagecontroller configured and operable to determine the focal conditionbased on said distance sensing data being indicative of the distancebetween the imaging unit and the target and controllably operate theimaging unit to successively perform the imaging sessions with thedifferent focal conditions.

The imaging unit may define a plurality of different imaging channels,in which case said image controller determines a time sequence ofoperation of the flash illuminator unit and of the different imagingchannels based on one or more of the following: the focal conditions ofthe imaging channels, the movement of the optical probe, and saiddistance sensing data being indicative of the distance between each ofthe imaging channels and the target, to thereby obtain the plurality ofimages.

In some examples, the image controller is configured to spatially dividethe target into one or more sections and allocate one or more imagingchannels for imaging each of said one or more sections. For example, theimage controller may allocate a number of the imaging channels forimaging each of said one or more sections, such that fields of view ofthe imaging channels in each section either overlap or are shifted alongthe movement path of the optical probe, the plurality of images therebycovering the whole target.

In some embodiments, the flash illuminator unit comprises one or morelighting elements associated with each imaging channel defined by theimaging unit. Each lighting element, associated with each imagingchannel, is arranged with a different angular orientation with respectto an optical axis of the imaging channel. The control unit determinesan angle between the target location and the optical axis of the imagingchannel, and selects, for each imaging session, one or more of thelighting elements to provide uniform illumination of the target.

In some embodiments, the control unit further comprises a flashcontroller configured and operable to control at least one ofillumination intensity, illumination angle and illumination time patternof the flash illuminator unit. The flash controller may be configuredand operable to control the at least one of illumination intensity,illumination angle and illumination time pattern of the flashilluminator unit based on one or more of the following: input motiondata indicative of the movement path of the optical probe in thevicinity of the target location, number of lighting elements of theflash illuminator unit, distance of a focal plane, exposure time,ambient light, an angle between the target and the flash illuminatorunit, reflectivity of target, type of the target, and type of a part ofthe target being imaged.

The system may further include a movement detection unit configured andoperable for providing input motion data to at least one of the controlunit, an image controller and a flash controller, for controlling theimaging sessions and a time sequence of operation of the flashilluminator unit and of the different imaging channels.

In some embodiments, the optical probe comprises a housing containingthe flash illuminator unit, the imaging unit, and the sensing unit. Thehousing may comprise a portion thereof formed with a mesh screencomprising an array of features arranged substantially parallel to themovement path of the optical probe, and/or at least one optical windowaligned with a respective at least one imaging channel defined by theimaging unit. The imaging of the target can be performed via the meshscreen and/or the optical window.

In some embodiments, the optical probe comprises at least one lightdirecting element associated with a respective at least one imagingchannel defined by the imaging unit, for collecting input light from thetarget and directing collected light to propagate along said imagingchannel to a detector of the imaging unit. The lighting element ispositioned either upstream or downstream of the light directing elementwith respect to a direction of propagation of the input light.

In some embodiments, the housing is configured as a two-part device,where a first part accommodates the flash illuminator unit and theimaging unit, and a second part accommodates the light directing elementand the sensing unit. The first and second parts of the housing areconfigured for a relative rotation between them about an axis of theimaging unit.

In some embodiments, the optical probe comprises a plurality of theimaging sets, each imaging set being configured with a field of view ofa different angular orientation with respect to an axis of the opticalprobe.

In some embodiments the system also includes an indication unitconfigured and operable to provide indication about an operational stateof the optical probe.

In some embodiments, the system includes a position controllerconfigured and operable to control one or more of the following: aposition of the optical probe, an orientation of the optical probe, anorientation of the movement path of the optical probe with respect tosaid target location, based on input position data. The positioncontroller may be configured and operable for communication with anexternal information source to receive said input position data. Theposition controller may be configured and operable for accessing theinput position data stored in a database of an inspection history.

In some embodiments, the system is configured for properly imaging theentire target having a certain depth (depth profile) larger than thedepth of focus of the imaging unit. The position controller isconfigured and operable to determine a pitch distance, along themovement path, between consecutive plurality of images being acquired bythe imaging unit, and control the motion and image acquisition of theimaging unit to capture the plurality of images such that each image isacquired at a different location along the depth profile of the target,thereby enabling generating focused images of the target along the wholedepth of the target.

In some embodiments, the system includes at least one additional imagingunit configured for defining one or more measurement channels, forperforming at least one of spectrophotometry, multi-spectral andUV-fluorescence measurements.

In some embodiments, the sensing unit comprises a plurality of distancesensing elements arranged in a spaced-apart relationship on a sensingsurface having a predetermined geometry. Each of the distance sensingelements provides distance data indicative of a distance from thedistance sensing element to the target location, the distance sensingdata provided by the sensing unit being therefore indicative of a planeor volume map of the vicinity of the target location depending on thegeometry of said sensing surface.

In some embodiments, the sensing unit comprises a one-dimensional arrayof distance sensing elements arranged transversely to the movement pathof the optical probe and the imaging unit defines a two-dimensionalarray of imaging channels such that each distance sensing element isassociated with a one-dimensional array of the imaging channels arrangedin a spaced-apart relationship along the movement path of the opticalprobe.

In some embodiments, the system includes a distance controlling unitcomprising a distance restriction assembly configured and operable toprevent the target from getting closer than a minimal focal distance ofthe imaging unit. The distance controlling unit may include at least onecontact sensor configured and operable to detect at least a partialcontact between the target and the distance restriction assembly andgenerate a contact signal indicative of the at least partial contact.For example, the distance controlling unit may include a plurality ofsuch contact sensors associated with different parts of the distancerestriction assembly, where each of the contact sensors detects at leasta partial contact between the target and the respective part of thedistance restriction assembly and generates a respective contact signalindicative of the at least partial contact. The control unit comprises aposition controller configured and operable to be responsive to thecontact signal(s) from the contact sensor(s) to initiate the imagingsession(s) using one or more respective imaging channels of the imagingunit.

In some embodiments, the system includes a positioning assemblyconfigured and operable to control the movement path of the opticalprobe in the vicinity of the target and adjust a position of the opticalprobe with respect to the target location, to enable one or more of thefollowing: imaging underside, upper side or side of a plant part by theimaging unit, and reduce image smearing and blur during relative motionbetween the optical probe and the target. In some examples, thepositioning assembly may include a rotatable telescopic member or avertically extending telescopic pole carrying the optical probe.Alternatively or additionally, the positioning assembly comprises anorientation imaging sensor configured and operable to provide path dataindicative of one or more obstacles or target parts located in themovement path of the optical probe. The control unit may be configuredand operable to receive and analyze said path data, and selectivelycarry out at least one of the following: upon identifying the targetparts in the path data, control the movement path of the optical probein order to bring the target parts into the focal range of the imagingunit, and upon identifying one or more of the obstacles in the path datacontrol the movement path of the optical probe in order to preventcollision of the optical probe with the obstacles. In some embodiments,the control unit is configured and operable to receive and analyze saidpath data by comparing the path data to previously collected data toenable selecting the target to be imaged.

In some embodiments, the positioning assembly is configured and operableto cause continuous or intermittent movement of the optical axis of theoptical probe to compensate for a relative motion between the opticalprobe and the target. In some examples, the positioning assembly may beconfigured and operable to rotate the optical axis of the optical probesuch that the optical axis scans around a conic surface, where a vectorof the relative motion between the target and the optical probe istangential to a base of the conic surface and is substantially equal toa vector of the movement of the optical axis when the optical axispoints to the target. Alternatively, or additionally, the positioningassembly may be configured and operable to oscillate the optical axis ofthe optical probe along an oscillation path, where a vector of therelative motion between the target and the optical probe is tangentialto at a least a portion of the oscillation path and is substantiallyequal to a vector of the movement of the optical axis when the opticalaxis points to the target.

In some other examples, the positioning assembly is configured andoperable to maintain said optical axis of the optical probe in astationary position during the relative motion between the optical probeand the target, and, in response to data indicative of a condition thatthe target is entering an object plane of the imaging unit, controllablymove the optical axis such that the relative motion between the targetand the optical axis across the object plane is compensated and an imageof the target is acquired.

In some embodiments, the system includes a plant shifting mechanismconfigured and operable to shift at least a part of the target withrespect to the movement path of the optical probe. For example, theplant shifting mechanism is configured and operable to selectively carryout at least one of the following: shift said at least part of thetarget out of the movement path of the optical probe; and shift said atleast part of the target towards the optical probe during movement andbring said plant part into the focal range of the imaging unit. Theplant shifting mechanism may comprise parallel slides that are sloped ata leading edge of the optical probe and flattened at a distance fromimaging channels of the imaging unit not exceeding a focal distance ofthe imaging unit.

In some embodiments, the imaging unit comprises a leaf imaging opticalprobe. For example, the leaf imaging optical probe may comprise adownward facing imaging element and an upward facing imaging element,whereby fields of view of the imaging elements essentially overlap,enabling imaging of both sides of a plant leaf without turning the plantleaf. In some other examples, the leaf imaging optical probe maycomprise at least one flash illuminator element configured and operableto illuminate both sides of the plant leaf, and reflected light imagingis performed on one side of the leaf either simultaneously orsequentially with transmitted light imaging on the second side of theleaf.

The system may also include a chute configured to receive therein theplant leaf and enable said imaging of at least one side of the plantleaf by the leaf imaging optical probe.

The leaf imaging optical probe may comprise one or more of thefollowing: a leaf holder assembly, a leaf guiding assembly, a leafflattener assembly, and a leaf cutter assembly.

In some embodiments, the system comprises a purifier device configuredand operable to decontaminate the optical probe. The purifier device mayutilize one or more of the following to decontaminate the optical probe:heat, electrostatic electricity, vibration and or immersion in apurifying compound.

In some embodiments, the imaging unit is configured to capture aplurality of images of the target, each of the images with a differentfocal condition γ The inspection system further comprises an imageanalyzer configured and operable to detect in-focus portions in each ofthe plurality of images and merge the in-focus portions into a singlein-focus image of the target.

In some embodiments, the imaging unit is configured to acquire aplurality of images of the target, each of the images being acquiredwith different imaging conditions including at least one of anillumination intensity and illumination angle. The inspection systemfurther comprises an image analyzer configured and operable to detectoptimally-illuminated portions in the plurality of images and merge theoptimally illuminated portions into a single image of the target.

In some embodiments, the inspection system is configured as a hand-helddevice. The hand-held device may be of one of the followingconfigurations: (i) the hand-held device comprises a common housingcarrying said optical probe and said control unit; and (ii) thehand-held device is configured as a two-part unit carrying the opticalprobe and the control unit in respective first and second unit partsconfigured to be connected to one another.

In some embodiments, the inspection system is configured to be carriedby a drone. The drone may comprise a plurality of rotors. The imagingunit may be mounted on an underside of the drone between the rotors. Theinspection system may further comprise a wind blocking strip mountedbetween the rotors and a frame mounted inside the focal range of theimaging unit and below the wind blocking strip, with an offset along amovement direction of the drone. The drone can thus approach a plantleaf such that during the drone movement the leaf is brought between thewind blocking strip and the frame while the wind blocking strip affectsa Bernoulli effect on the leaf keeping it floating until a point where adowndraft force of the rotors pushes the leaf downwards towards theframe and the at least one imaging unit acquires focused images of theplant leaf.

The invention also provides a vehicle carrying the above-describedinspection system. This may be a ground vehicle or as a flying platform.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosedherein and to exemplify how it may be carried out in practice,embodiments will now be described, by way of non-limiting example only,with reference to the accompanying drawings, in which:

FIG. 1 illustrates a non-limiting example of an inspection systemconfigured in accordance with the principles of the present invention;

FIGS. 2A-2F illustrate non-limiting examples of the optical probe of theinspection system, in accordance with various applications of thepresent invention;

FIGS. 3A-3I illustrate non-limiting examples of positioning assembly ofthe inspection system and/or optical probe with respect to the targetplant; and

FIGS. 4A-4D3 illustrate non-limiting examples of a leaf imaging opticalprobe of the inspection system, in accordance with various applicationsof the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is made to FIG. 1 illustrating by way of a block diagram anon-limiting exemplary embodiment of an inspection system 100 configuredand operable for monitoring plants' conditions in one or more plantgrowth areas. For example, as shown, the inspection system 100 isconfigured to monitor one or more conditions of a plant 10, and morespecifically a leaf 10L on the plant 10. The inspection system 100includes an optical probe 102 configured and operable for collectinghigh-resolution characterization data from the plant 10 and a controlunit 104 connected to the optical probe 102 by known in the artcommunication means 106, either wired or wireless communication, toexchange data therebetween. While not shown, the optical probe and thecontrol unit can be equipped with suitable communication utilities, asknown in the art, for enabling the data communication. It should benoted, however, that in some embodiments, the control unit 104 may be anintegral part of the optical probe 102, and in this case thecommunication is done internally.

The optical probe 102 is configured to be brought close to the targetand includes at least one flash illuminator unit 102A, at least oneimaging unit 102B, and at least one sensing unit 102C, to perform one ormore imaging sessions on the target, i.e. plant 10, at the targetlocation, during a movement of the optical probe in the vicinity of theplant location, as illustrated by the movement/velocity vector V thatpoints in the direction of the path of movement of the optical probe.

The sensing unit 102C includes a distance sensing element (in thisnon-limiting example, the sensing unit 102C is the distance sensingelement), configured and operable to provide data enabling to determinean instantaneous distance D1 between the imaging unit 102B and thetarget location at plant 10, presented by a point/portion of interestPOI at a leaf 10L of the plant 10, and generate distance sensing dataDSD indicative thereof. In the described example, the sensing unit 102Cmeasures the instantaneous distance D3 between the sensing unit 102C andthe target POI where D3 is indicative of the distance D1 between theimaging unit 102B and the target POI, and more specifically D1 isindicative of the distance between the focal distance/plane of theimaging unit 102B and the target POI. The distance D1 can be obtainedfrom the distance D3 based on previously known relation between them.The distance sensing element may be an optical sensor, an acousticsensor, or other type of distance determining sensor.

The control unit 104 is configured and operable to be responsive to thedistance sensing data DSD, via the communication means 106, tosynchronize operation of the flash illuminator unit 102A and the imagingunit 102B to successfully perform the imaging sessions by the opticalprobe 102. The control unit 104 is a computer-based system and as suchis configured with an input utility 104A and output utility 104B forreceiving and sending data. Also, the control unit 104 includes a dataprocessing and analyzing utility 104C that continuously analyzes theinstantaneously received distance sensing data DSD and generatescorresponding one or more signals to controllably activate the flashilluminator unit 102A and the imaging unit 102B. As shown in the figure,a distance D2 between the sensing unit 102C and the imaging unit 102Balong the path of movement of the optical probe can bepredetermined/known and used by the control unit 104 to determine thetime at which the imaging session should be initiated or carried out, tothereby timely activate the flash illuminator unit 102A and the imagingunit 102B, with the respective imaging parameters, e.g. illuminationintensity, illumination angle and illumination duration/time pattern ofthe flash light produced by the flash illuminator unit 102A, and time ofimage capture by the imaging unit 102B. By having access to the velocityof movement along the movement path, the control unit 104 can calculatethe time passing between the moment at which the sensing unit 1020detects the target POI and the moment at which the flash illuminatorunit 102A and/or the imaging unit 102B reach the target POI. In someembodiments, the target POI presents the edge of the target, e.g. theedge of a leaf, i.e. it is the first encounter between the sensing unit102C and the target to be imaged. In this case, the initiation time ofthe imaging session is determined and the flash illuminator unit 102Aand the imaging unit 102B are operated to start the imaging sessionswhich can last and extend over the whole target/leaf.

The imaging unit 102B defines one or more imaging channels eachconfigured to provide high-resolution imaging. In this example, oneimaging channel ICH is illustrated. The high-resolution imagingchannel(s) capture(s) images of parts of plants, mainly flowers, leaves,fruit and branches, with the aim of detecting small elements such aspests, diseases and beneficial insects. Each high-resolution imagingchannel has an optical resolution capable of imaging small elements toenable accurate recognition and classification. For example, the opticalresolution is in the range of one micron to one hundred microns. Forexample, the field of view can be in the range of multiple millimetersto multiple centimeters. The high-resolution imaging unit 102B canenable detection, classification and mapping of the presence ofdetrimental conditions, e.g. detection and classification of the type ofpests and its development phase (e.g. egg, larvae, adult), while alsoenabling, among others, analysis of the local ratio of beneficialinsects to pest insects.

In some embodiments, in order to enable capture of high-resolutionimages without potential smearing effects caused by motion, either veryshort exposure times are performed, or the target and imaging channelare maintained with small differential motion during the image capture.

In order to detect many types of pests and diseases, the optical probe102 can be configured to perform imaging of the underside of leaves, asthat is the preferred habitat of many such pests, especially at theearly stages of the pest development. The underside of leaves is lessaccessible to imaging from a stand-off position, since plants grow withleaf upper side facing outwards and upwards towards solar illumination.

Plant parts that are imaged in high-resolution, such as flowers, leaves,fruit and branches are essentially non-planar objects. Also, theunderside of leaves of many types of plants is not a flat plane at themillimeter scale, potentially resulting in pests being partially hiddenalong protruding veins or along varying distances of different parts ofthe leaf from a flat focal plane. Therefore, in some exemplaryembodiments, the imaging unit 102B is configured and operable to acquirea plurality of images with different focal conditions within a focalrange of the imaging unit during the imaging sessions.

For example, the imaging unit 102B can be configured with a plurality ofdifferent imaging channels of the same optical resolution and differentfocal conditions, the distance sensing data DSD in this case may beindicative of the distance between each of the plurality of imagingchannels and the target to be imaged. Additionally or alternatively, theimaging unit 102B may define at least one imaging channel that isconfigured with an adaptive/variable focus, within the focal range ofthe imaging unit, for imaging along the at least one imaging channel,the distance sensing data DSD in this case may be indicative of thedistance between each of the at least one focus-variable imaging channeland the target to be imaged.

In some embodiments, the optical probe 102 can be accommodated within ahousing 102D containing the flash illuminator unit 102A, the imagingunit 102B, and the sensing unit 102C. The housing may further include aportion thereof formed with at least one optical window 102E alignedwith a respective at least one imaging channel ICH defined by theimaging unit 102B, to enable imaging of the target via the at least oneoptical window. At least part of the flash illuminator unit 102A can beaccommodated within a peripheral region of the optical window 102E. Forexample, the optical window can have a circular shape while the at leastpart of the flash illuminator unit can have a ring shape surrounding theoptical window.

In some embodiments, the housing 102D contains, instead of or inaddition to an optical window, a portion thereof formed with at leastone mesh screen (not specifically shown) aligned with a respective atleast one imaging channel defined by the imaging unit 102B to enableimaging of the target via said at least one mesh screen. In one example,the mesh screen essentially includes an array of parallel lines/wiresarranged parallel to a desired direction of the path of movement of theoptical probe 102.

In some embodiments, the housing 102D includes a portion thereof,specifically a portion located upstream the sensing unit 102C (withrespect to target location or path of movement of the optical probe),configured and operable as an aligner portion 102F that comes intocontact with the plant part to be imaged such that it causes the plantpart to align with respect to the flash illuminator unit and/or theimaging unit during the imaging sessions. For example, the alignerportion may act on the plant part to flatten it.

In some embodiments, the control unit 104 may include an imagecontroller 104D configured and operable to controllably operate theimaging unit 102B to successively perform the imaging sessions, possiblywith the different focal conditions. In some embodiments, the imagecontroller 104D is configured and operable to determine the focalcondition based on the distance D2 being indicative of the distancebetween the imaging system unit and the target. The distance D2 may formpart of the distance sensing data DSD. The image controller 104D can beconfigured to determine the time sequence of operation of the flashilluminator unit and of the different imaging channels based either ontheir focus conditions, on the movement of the optical probe or on thedistance sensing data DSD that is indicative of the distance betweeneach of the imaging channels and the target. The image controller 104Dcan be configured to spatially divide the target into one or moresections and allocate one or more imaging channels for imaging eachsection, the plurality of images thereby covering the whole target. Theimage controller 104D may define the one or more sections such thatfields of view of the one or more imaging channels in each sectionoverlap. The image controller 104D may define the one or more sectionssuch that fields of view of the one or more imaging channels are shiftedalong path of movement of the optical probe, for example the imagingchannels are configured to capture images of respective sectionsarranged one after the other along the path of movement of the opticalprobe.

During image capture, the target may be illuminated by a flash or strobelight with short illumination time to prevent image smearing due to themovement of the optical probe with respect to the target. The flashilluminator unit 102A may include a single light source/lightingelement, or multiple lighting elements, associated with each imagingchannel ICH. For example, a ring of light sources surrounding the focusarea can be provided. Each of the one or more lighting elements,associated with each imaging channel, can be aligned at a differentangle with respect to optical axis of the imaging channel, and thecontrol unit 104 can be configured and operable to determine the anglebetween the target location and the optical axis of the imaging channel,and select, for each imaging session, one or more of the one or morelighting elements to provide uniform illumination of the target.Multiple exposures may be performed at a frequency that can be adjustedto match the movement velocity of the optical probe and the size of thetarget. Pests or other elements of interest within the images can becaptured in multiple images, thereby providing multi-angle data andenabling formation of a three-dimensional model of the object ofinterest. This can potentially aid in recognition and classification ofthe object of interest. The data from multiple images may be combined toform a two-dimensional image or three-dimensional model of the target.

The flash illuminator unit 102A can include multiple addressablelighting elements assigned to the different portions of the focal areaand aligned to provide separate preferable illumination for each of theportions. The illumination may provide white light, red light or otherspectral as well as various spatial options such as on-axis or obliqueaxis illumination. In some embodiments, a red low spatial frequencyblocking filter can be added at a Fourier plane of the object in orderto block green light received from the object and thereby reduce theintensity of essentially featureless green areas of the plants.

In some embodiments, the control unit 104 further includes a flashcontroller 104E configured and operable to control at least one ofillumination intensity, illumination angle and illumination time patternof the flash illuminator unit 102A. The flash controller 104E maycontrol the at least one of illumination intensity, illumination angleand illumination time pattern of the flash illuminator unit based oninput motion data indicative of the path of movement of the opticalprobe in the vicinity of the target location. The flash controller 104Ecan be also configured and operable to determine the illuminationintensity, illumination angle and illumination time pattern based on oneor more of the following: number of lighting elements of the flashilluminator unit, distance of focus plane, exposure time, ambient light,angle between the target and flash illuminator unit 102A, reflectivityof target, type of target plant, and type of part of the target plant.The inspection system may further include a movement detection unit 107configured and operable for providing input motion data to the controlunit 104, image controller 104D, flash controller 104E and/or positioncontroller (described below), for controlling the imaging sessions andtime sequence of operation of the flash illuminator unit and of thedifferent imaging channels, including at least one of illuminationintensity, illumination angle and illumination time pattern of the flashilluminator unit 102A. For example, as shown in the figure, the movementdetection unit 107 can be integrated in the optical probe 102. Themovement detection unit 107 can form part of the sensing unit 102C, forexample at least part of the sensing unit provides the input motion dataindicative of the path of movement of the optical probe in space. Themovement detection unit may also be located in the control unit or on avehicle carrying the optical probe and/or the control unit. In someembodiments, the input motion data includes one or more of position,velocity vector and/or acceleration vector.

In some embodiments, the optical probe 102 includes a plurality of sets,each set includes a flash illuminator unit, a respective imaging unitand a respective sensing unit and each set is oriented in a differentspatial and/or angular direction with respect to an axis of the opticalprobe. This enables capturing images from multiple directions, thusfacilitating the data collection and the reconstruction of thethree-dimensional model of the plant part under examination. Each setmay be associated with respective image controller and flash controllerconfigured and operable as described above. In one example, a first setof a flash illuminator unit, a respective imaging unit and a respectivesensing unit faces upwards, a second set faces downwards, and a thirdset faces horizontally.

In some embodiments, the inspection system includes an indication unit108 configured and operable to provide indication about an operationalstate of the optical probe. The operational state can be, for example:on/off, waiting for target identification, target has been identified,capturing images of target, failure message(s), etc. The indication unit108 may utilize audio, visual and/or vibration signals to indicate thespecific operational state of the probe. The indication unit 108 can beparticularly useful when the optical probe is manually carried andoperated by a worker in the field.

In some embodiments, the inspection system further includes, as part ofthe imaging unit 102B or as a standalone device, an imaging deviceconfigured and operable for defining one or more measurement channels,for performing at least one of spectrophotometry, multi-spectral andUV-fluorescence measurements, for characterizing the target plant.

In some embodiments, the sensing unit 102C includes a plurality ofdistance sensing elements arranged in a spaced-apart relationship on asensing surface having a predetermined geometry, each of the distancesensing elements providing distance data indicative of a distance fromthe distance sensing element to the target location, the distancesensing data provided by the sensing unit being therefore indicative ofa plane or volume map of the vicinity of the target location dependingon the geometry of the sensing surface. For example, the sensing surfacemay trace a cylindrical surface, a spherical surface, a flat surface,etc.

In some embodiments, the sensing unit 102C includes a one-dimensionalarray of distance sensing elements arranged transversely to path of themovement of the optical probe and the imaging unit defines atwo-dimensional array of imaging channels such that each distanceelement is associated with a one-dimensional array of the imagingchannels arranged parallel to the path of movement of the optical probe.

In some embodiments, the imaging unit 102B includes multiple imagingsensors with respective separate focusing mechanisms. The sensing unit102C may include multiple distance sensing elements for measuringdistances to different areas of at least one target. The flashilluminator unit 102A may include multiple lighting elements forillumination of the at least one target. In some examples, the multipleimaging sensors and/or distance sensing elements and/or lightingelements are located in a two-dimensional plane, arranged in a line, ina circle or in other patterns within the plane. The multiple imagingsensors and/or distance sensing elements and/or lighting elements mayalso be located on a three-dimensional surface such as a cylinder or arectangular box. The multiple distance sensing elements may be arrangedin a pattern on the surface to enable building a three-dimensionaldistance map of the at least one target.

Multiple imaging sensors may be located in a linear arrangement parallelto the path of movement of the optical probe. In one embodiment, theimaging sensors are triggered sequentially, with a time delay dependingon the forward movement velocity, such that each of the imaging sensorscaptures an image of essentially the same part of the plant. The timedelay is essentially equal to the distance between the cameras dividedby the velocity of the movement. Separate illumination flashes can beoperated for each imaging sensor. The separate imaging sensors mayoperate with different focal distances, to build a three-dimensionalimage of the plant part by focus stacking, as will be described furtherbelow. The separate imaging sensors may also operate with differentillumination intensity levels to enable capturing of images with optimalexposure levels or for combining images of objects with different levelsof reflectivity into a composite image with optimal exposure level. Theexposure levels may be adjusted to compensate for changes in targetdistance, target angle, target reflectivity, ambient illumination andothers. The intensity levels may also be adjusted in conjunction withthe different focal distance of each imaging sensor.

In some embodiments, the distance between the imaging sensors is lessthan the width of the field of view of the imaging sensors at the targetplane, enabling overlap of the fields of view of the imaging sensors.When the delay between imaging operation of sequential imaging sensorsis less than the inter-sensor spacing divided by the velocity, thedifferent imaging sensors may provide images of essentially the sameobject from different angles enabling formation of stereoscopic imagesfor extraction of three-dimensional information.

In some embodiments, at least two imaging sensors may be adjusted sothat their optical axes are not parallel, but essentially pointing tothe same location at the nominal target plane. At least two images maybe captured simultaneously to enable formation of detailed stereoscopicimages for extraction of three-dimensional information.

Multiple images from multiple directions may be used to produce acontinuous image of the circumference of a semi-cylindrical target suchas a leaf's vein in order to detect and recognize pests that hide inrecesses along the veins.

When at least one target enters the range of the distance sensingelement(s), the control unit 104, specifically the data processing andanalyzing utility 104C, processes the distance signals DSD and builds athree-dimensional model of the location of the target. If the at leastone target is not located in sufficient proximity to the imagingsensor(s), the control unit 104 may generate a signal, requesting tocorrect the location of the imaging unit with respect to the target inorder to optimize distance for the capturing of images of the at leastone target. Based on the distance information, the control unit definesthe focus distance setting for each of the imaging sensors of theimaging unit in order to capture focused images of the different areasof the at least one target. The control unit also defines the specificlighting elements to be operated in order to provide uniformillumination for the imaging sensors to be operated. Images may becaptured simultaneously during a simultaneous light pulse, orsequentially with separate pulses.

As will be described further below, the inspection system may processthe images or may send the images to an external image analysis utilityto process the images. Processing of the images may include combiningin-focus areas of each of the images from the multiple imagingsensors/channels into one image containing an extended in-focus area.The in-focus area for each imaging sensor/channel may be determined bycombining the nominal camera focus range (e.g. depth of focus, depth offield or other definition) with the data from the three-dimensionaldistance map and finding the in-focus areas of the three-dimensionalsurface. The inspection system may vary the parameter for determiningthe focus range in order to decrease or increase the overlap ofinformation from the different imaging sensors/channels on thethree-dimensional surface. Based on the known focus setting of eachimaging sensor/channel, the inspection system may perform magnificationnormalization and distortion correction of the images prior to combiningthem. The inspection system may analyze the separate images and detectin-focus areas in the separate images and combine them into a singleimage containing the multiple in-focus areas. The inspection system maydetect localized in-focus elements of interest in the separate imagesand combine them into an image containing multiple localized in-focuselements.

The inspection system, e.g. the control unit, may define which imagingsensor(s) or unit(s) will be used in order to minimize data file size ifit detects that certain areas will have over-redundancy of multipleimages or if certain areas will not contain a target in focus. Theinspection system may delete images after image capture as well, basedon the results, e.g. if there are no in-focus areas in the images. Theinspection system may operate all the imaging sensors and/or lightingelements or a subset thereof depending on the three-dimensional shape ofthe target. Depending on the geometry of the surface containing thedistance sensing elements, the three-dimensional map may be formed abovea plane containing the distance sensing elements, if the distancesensing elements are located on a plane, or if the distance sensingelements are located on a cylindrical surface, the three-dimensional mapmay be formed in the cylindrical volume surrounding the cylindricalsurface.

The location of the sensing unit(s), flash illuminator unit(s) andimaging unit(s) on the housing of the optical probe may be determined bythe type of plant to be inspected. Different types of plants may havedifferent typical angles of their leaves depending on plant species,plant age, plant hydration and other factors. Angle of the imagingchannel(s) with respect to the target may be varied in order to enableessentially perpendicular imaging and increase the proportion ofin-focus areas of the captured images. The angle may be controlled byproviding a rotating portion of the optical probe that adjusts the angleduring operation, or may be preset in manufacturing of the optical probemaking the optical probe specific to a specific kind of crop.

The optical probe may be surrounded, at least at the vicinity of theoptical window, by a mesh casing or screen that prevents direct contactof parts of the target plant with the functional parts of the imaging(the flash illuminator unit and the imaging unit). The meshcasing/screen may be designed with high opening/blocking ratio tominimize the blocking of the images. The distance of the mesh from theimaging unit is designed to prevent the plant parts from getting closerthan a minimal focal distance.

The mesh surrounding the optical probe may contain at least one contactsensor (as will be further described below) which detects when a part ofa plant comes into contact with the mesh. The signal generated by thesensors may be processed and used to trigger illumination and imagecapture. Sensors in specific parts of the mesh may be used to triggerspecific imaging sensors of the inspection system.

Reference is made to FIGS. 2A-2F illustrating non-limiting examples ofdifferent configurations of the optical probe 102, in accordance withthe present invention. Different physical and/or optical designs of theoptical probe can be considered. For example, the imaging channel ICHstarting at the target, passing through an optical window in the housingand ending at a detector of the imaging unit may not be straight, i.e.may not be on-axis imaging channel, as illustrated generally in FIG. 1 ,but a broken optical path, i.e. a folded axis imaging channel, asillustrated in FIGS. 2A and 2B. This can be due to physical constrainssuch as size of the imaging unit used against the optimal size of thehousing of the optical probe to provide effective positioning and accessof the optical probe to the different plant parts. Sometimes, it ispreferable to minimize the height of the housing of the optical probe asmuch as possible, resulting, for example, in placing the imaging unit inan off-axis position with respect to the optical window, as in FIGS. 2Aand 2B. Sometimes, it is preferable to minimize the length of thehousing of the optical probe as much as possible, resulting, forexample, in placing the imaging unit beneath the optical window, as inFIG. 1 .

When the imaging unit is placed off-axis with respect to the opticalwindow, as in FIGS. 2A and 2B, the optical probe further includes atleast one light directing/reflecting element 102G, such as a mirror,that directs the light along the imaging channel. Also, as illustratedin the figures, the optical probe may include a light focusing element102H, such as a lens, placed before the imaging unit, in particularbetween the at least one directing element 102G and the imaging unit102B. The folded-axis configurations enable, among others, smallmechanical cross-section with relation to the direction of motion whilestill enabling full field of view. The sensing unit 102C may be placedat different locations in relation to the optical axis (upstream of thelight directing element 102G with respect to a direction of propagationof the input light) with a detection axis parallel to the optical axis,enabling positioning the imaging channel ICH downstream of the directionof path of movement (direction V as shown), upstream of the direction ofpath of movement or at different angles in between.

As illustrated in FIG. 2A, at least one lighting element 102A1 of theflash illuminator unit 102A associated with the respective at least oneimaging channel is positioned upstream of the light directing element102G with respect to a direction of propagation of the input light. Inthis example, the at least one lighting element 102A1 is external withrespect to the housing. The optical window 102E can be located adjacentto the illuminator unit 102A1, without any distance therebetween,enabling sealing of the housing. Also, this configuration has lessparasitic scattered light originating from the lighting element 102A1,thus enhancing flash efficiency and image clarity while saving energy.

As illustrated in FIG. 2B, at least one lighting element 102A2 of theflash illuminator unit 102A associated with the respective at least oneimaging channel is positioned downstream of the light directing element102G with respect to a direction of propagation of the input light. Inthis example, the at least one lighting element 102A2 is internal withrespect to the housing. The optical window 102E can be located betweenthe target and the light directing element 102G, facilitating sealing ofthe housing with the window.

In FIG. 2C1, the optical probe 102 is accommodated in a two-parthousing, such that the flash illuminator unit 102A and the imaging unit102B are accommodated in a first housing part 102D1, and the sensingunit 102C and a light directing element 102G are accommodated in asecond housing part 102D2. This configuration enables, among others, thepossibility to rotate the second housing part 102D2 around the opticalaxis OA, thereby enabling rotation of the object plane and rotating thefolded optical axis OA1 while maintaining the sensing unit 102C alignedto the object plane as illustrated in FIG. 2C2. This enables access totargets in different directions around the optical probe, as illustratedin three such directions (down, diagonally up, right), while using oneflash illuminator unit and one imaging unit oriented in only onedirection. In some embodiments, the position of sensing unit 102C andthe rotation rate can also be adjusted to essentially cancel therelative motion of the target relative to the optical probe.Alternatively, when the optical probe is located within a singlehousing, the whole housing can be mounted on a rotatable joint/pivotthat rotates the housing and enables capturing images of plant partslocated in different directions relative to the optical probe.

As mentioned above, the optical probe may contain at least onereflective optical element, which is located within the field of view ofthe imaging unit, at an axial distance close to the object plane wherethe reflective element tilts the angle of the rays to cause the imagingunit to image an off-axis area instead of an on-axis or near-axis area.In some embodiments, two mirrors are placed within the field of view ofthe imaging unit, such that one causes an area above the optical axis tobe imaged onto a first portion of the imaging sensor, and a secondmirror causes an area below the optical axis to be imaged onto a secondportion of the imaging sensor and a third unaffected area of the fieldof view is imaged onto a third portion of the imaging sensor. In aspecific embodiment, the first mirror causes an essentiallyupward-facing perpendicular axis to be formed at an object plane and thesecond mirror causes a downward-facing perpendicular axis at a secondobject plane to be formed, and the imaging sensor contains separateimage areas formed from the first object plane, the second object planeand portion of the non-deflected original object plane. In an additionalembodiment, the mirrors may be rotated around the optical axis to enableimage capture of various targets off the optical axis. In an example,the different areas of the plant may be the underside of a first leaf,the top side of a second leaf and the stem of the plant. The position ofthe optical axis may be maintained at a height essentially half waybetween the upward facing top side of a leaf and the downward facingunderside of a leaf, while pointing at a stem of the plant in thenon-deflected direction. The distance sensing element(s) of the sensingunit may be used to measure the distance to the objects of interest andbring the optical system to a position essentially equidistant tomultiple objects of interest. Alternatively, the system may determine amotion path where the different parts of the plant are brought to focussequentially.

FIG. 2D illustrates a non-limiting example of an optical probe 102accommodated in a housing 102D having a rectangular box shape, with fouror five sets of flash illuminator unit 102A having a ring shape, imagingunit 102B and distance sensing unit 102C, mounted on each one of therectangular surfaces of the box and defining four or five sensingsurfaces. This enables high flexibility for capturing images of theplants without the need to turn and move the optical probe frequently.The direction of motion (motion axis) V is defined to enablesimultaneous capturing of images in the forward, upward, downward andsideways directions. The optical probe may also be inserted in a plantwhile generating distance data, then held in place and operatedstatically. A similar example may be implemented on a cylindrical box,with the cylinder axis perpendicular to the direction of motion.

FIG. 2E illustrates another non-limiting example of an optical probe 102accommodated in a housing 102D having a cylindrical shape, with one setof flash illuminator unit 102A, imaging unit 102B and distance sensingunit 102C, mounted on the surface of the cylinder and defining a sensingsurface. The distance unit includes a plurality of distance sensingelements, e.g. 102C1-102C3, arranged in a one dimensional array along atransverse direction to the motion axis of the optical probe, theimaging unit includes a plurality of imaging sensors, e.g. 102B1-102B6,arranged in a two-dimensional array along the longitudinal andtransverse directions, such that two imaging sensors are associated witheach distance sensing element located along the same line along thelongitudinal axis, the flash illuminator unit includes a plurality oflighting elements 102A1-102A6 associated with and surrounding theimaging unit.

FIG. 2F illustrates another non-limiting example of an optical probe 102accommodated in a housing 102D having a box-like shape, with a set offlash illuminator unit 102A, imaging unit 102B and distance sensing unit102C, mounted on multiple surfaces of the box and defining multiplesensing surfaces. The distance unit includes a plurality of distancesensing elements, e.g. three, arranged in a one dimensional array alonga transverse direction to the motion axis of the optical probe, theimaging unit includes a plurality of imaging sensors, e.g. nine,arranged in a two-dimensional array along the longitudinal andtransverse directions, such that three imaging sensors are associatedwith each distance sensing element located along the same line along thelongitudinal axis, the flash illuminator unit includes a plurality oflighting elements, e.g. six, associated with and surrounding the imagingunit.

As appreciated, various options of sets and arrangements are possibleenabling flexibility, efficiency and time management.

Reference is made to FIGS. 3A-3I illustrating non-limiting examples ofpositioning assemblies of the inspection system and/or optical probewith respect to the target plant. The positioning assembly(s) may beconfigured and operable to control path of the movement of the opticalprobe in a vicinity of the target and adjust a position of the opticalprobe with respect to the target location.

In some embodiments, as illustrated in FIG. 3A, the inspection system orat least the optical probe can be carried by a worker, the optical probe102 is configured as a hand-held device which the worker manually holdsand brings in proximity to the target plants in order to perform theimaging session(s). The control unit 104 can be carried by the worker,for example on his/her back as shown, or on the hand-held device.

In some embodiments, as shown for example in FIG. 3B, the inspectionsystem or at least the optical probe can be carried by a vehicle,specifically a robotic transportation vehicle, that travels in the areaof crops, e.g. along rows of crops, and is brought into proximity to theplants in order to capture images of the target plant parts such asflowers, leaves, fruit or branches. As shown, the vehicle can be aground vehicle 202 or a flying platform 204 (e.g. a drone).

The target locations to be inspected may be provided by an externalinformation source 302 and/or may be chosen autonomously by theinspection system and/or may be predetermined based on previousinspection history, and/or may be predetermined based on a path designedto provide effective statistical sampling of the area.

The positioning assembly includes a position controller 104F that may belocated in the control unit 104, as illustrated in the figure, or in thevehicle 202 or 204, or distributed therebetween. The position controller104F is configured and operable to control a position of the opticalprobe with respect to the target location based on input position data.The position controller 104F can be configured and operable tocommunicate with the external information source 302 to receive theinput position data. The position controller 104F can be configured andoperable to receive input data of the movement detection unit 107located in the optical probe, in the control unit or in the vehicle.Additionally or alternatively, the position controller 104F can beconfigured and operable for accessing the input position data that isstored in a database 402 of previous inspection history. The positioncontroller 104F can be configured and operable to control spatialorientation and/or path of movement of the optical probe with respect tothe target location, based on previously provided orientation data orbased on input from an orientation imaging sensor 206, as furtherdescribed below.

The external information source 302 can be configured to provide theinput position data or the orientation data to the position controller104F by analyzing previously captured images of the plants anddetermining candidate locations that are considered suspicious forpossible presence of pest or disease. The images may be captured by awide-area imaging channel that can be located on a separate vehicle oron the vehicle carrying the high-resolution channel. The analysis of theimages is carried out by the position controller 104F or by an imageanalyzer 104G located in the control unit (as shown) or in the externalinformation source or in both. In some embodiments, the image analyzermay be located on the vehicle carrying the high-resolution channel orthe wide-area channel, or it may be located in a separate location, suchas the control unit, while communicating with a controller on thevehicle carrying the high-resolution channel. The analysis of thewide-area images may define preferred targets and provide calculatedaccess paths for accessing those targets. For example, it may provideapproach vectors for the high-resolution channel to inspect the targetswhile providing for minimum physical interaction with the plant.

In one embodiment, a series of wide-area images covering most of theareas of a row of plants is analyzed by the position controller104F/image analyzer 104G for suspicious locations on plants which show apossible presence of pests, disease or other detrimental conditions.Based on the analysis, the position controller 104F/image analyzer 104Gprovides a series of preferred target locations which may includeflowers, leaves, fruits and branches of different plants along the row.The position controller 104F may also provide information on an approachpath for accessing the preferred targets. Furthermore, the positioncontroller 104F/image analyzer 104G may select certain targets locatedin close proximity to enable inspection with one approach path. Theposition controller 104F/image analyzer 104G may also provide an optimalsequence for inspecting the targets. If the time required for inspectingthe suspicious targets is less than a predefined time, the positioncontroller 104F/image analyzer 104G may add additional targets tooptimize a uniform coverage of the plant area up to a predefined maximumtime.

The target objects/plants may be defined in advance by the positioncontroller 104F as part of an inspection path, where specific areas ofthe crop are defined for specific types of samples. For example, wheninspecting a row of plants, the position controller 104F may defineareas of the row where leaves are to be examined (in x, y, zcoordinates), areas where fruit arc to be examined, areas where flowersare to be examined and areas where branches are to be examined. Leavesmay be examined on their top side, their bottom side or both. Theprocedure for automatically defining the areas to be examined may takeinto account the age of the plants, the height of the plants, previoushistory of findings on the plants, the season, the past weather history,the future weather forecast, the allotted time for inspecting the areaof plants and other factors. The position controller 104F may selectlocations where in a single approach, multiple targets may be accessed,for example a location where the top side of a leaf, a branch and abottom side of a leaf can all be viewed from a single access path. Theposition controller may also provide a general area to be examined,where the exact plant part to be inspected is determined whenapproaching the general area, based on input from the orientationimaging sensor 206.

Images captured during the approach to a target, by a wide-area imagingchannel or by an orientation imaging sensor, may be stored in thedatabase 402 and utilized later. If a disease or pest is found at thespecified target, the wide-area images from the approach may be utilizedfor improving correlations between wide-area images of a plant and thelocations in which diseases are present. The preferable images which maybe utilized may include at least one of an image of the pest or disease,an image of the plant part containing the pest or disease, and an imageof the plant including the vicinity of the plant part containing thepest or disease.

The target information transferred to the high-resolution inspectionsystem may be in the form of x-y-z coordinates, in the form of at leastone target reference image, in the form of a three-dimensionalcoordinate path, in the form of at least one target reference image anda three-dimensional path or any other format containing the requiredinformation.

As mentioned above, the positioning assembly may contain an orientationimaging sensor 206 with a wide-area field of view. The orientationimaging sensor 206 may be a conventional imaging camera or astereoscopic or other three-dimensional camera providing information ondistance as well as lateral location. The orientation imaging sensor 206may be mounted on the same optical probe as the high-resolution imagingunit or at a location on the vehicle, preferably more distant from therow of plants to maintain a wider field of view, or at another vehicleor in fixed locations in the plant growth area. The orientation imagingsensor 206 may be configured and operable to provide image path dataindicative of obstacle(s) or plant parts located in the path of movementof the optical probe. The control unit, specifically the positioncontroller 104F, is configured and operable to receive the path data andupon identifying plant parts in the path data, control the path ofmovement of the optical probe in order to bring the plant parts into thefocal range of the high-resolution imaging unit. Additionally oralternatively, the position controller is configured and operable tocontrol the path of movement of the optical probe in order to preventcollision of the optical probe with obstacles upon identifying one ormore obstacles in the path data. The position controller may also beconfigured and operable to receive and analyze the path data bycomparing the path data to previously collected data to enable selectingthe target to be imaged.

When the optical probe is in motion and passes above (or below) a targetto be imaged, the input from a forward-facing orientation imaging sensormay be used to adjust the height of the optical probe in order to bringa bottom (or top) facing focus area to the height of the target.

When approaching a specified target location, images from theorientation imaging sensor may be compared to a target reference imagereceived from the position controller and upon finding a highcorrelation between images, the target location is determined. As thevehicle approaches the plant, vertical height and lateral positionadjustments are made based on images from the orientation imaging sensorin order to accurately engage specified target. In the case where theinspected targets are chosen autonomously by the inspectionsystem/optical probe/position controller, the orientation imaging sensormay be used to determine the plant parts to be examined, such asflowers, fruit, leaves, branches, top side of leaves and underside ofleaves. Wide area images of the plant captured by the orientationimaging sensor may be analyzed by the position controller or by aprocessor on-board the vehicle, and candidate plant parts are selectedfrom the images based on, for example, accessibility, suspiciousdistortion, discoloration and other characteristics. The positioncontroller may provide coordinates and directions to reach the desiredlocation for inspection of the plant part. In one example, the vehiclecarrying the optical probe travels along a row of plants andperiodically stops at predetermined distances, captures a wide-areaimage of the plants, determines a target plant part and approach path,approaches the target on the path and performs inspection of the plantpart. In another example, the vehicle carrying the optical probe travelscontinuously along a row of plants and the position of thehigh-resolution optical probe is continuously adjusted to enable imagingwithin the plant foliage. In one specific example, the position of thehigh-resolution optical probe is adjusted to enable the optical probe topass underneath leaves, where the movement path of the probe in relationto the leaves is controlled in order to prevent entanglement and damageto the plant or probe.

The position adjustment enables bringing the probe to a focus positionrelative to the leaves, thereby enabling sampling of maximum number ofleaves while maintaining essentially constant forward motion along therow. The vertical position of the focal area of the optical probe may beadjusted by varying the height of the vehicle, by varying the height ofthe interface between the vehicle and the optical probe or by varying aninternal distance between optical elements in the optical probe.

In some embodiments, the high-resolution optical probe is mounted on adrone small enough to enter spaces between the leaves of the plant. Thedrone is preferably encased in a rounded net-like enclosure, throughwhich air can flow, enabling efficient flight, while gaps in thenet-like structure are small enough to prevent contact of the leaveswith the drone's moving parts. At least one optical probe/imaging unitis located within the net-like enclosure and attached above the drone,with an optional gimbaled mounting. Attaching the optical probe abovethe drone provides easy access to imaging underside of leaves. Thedowndraft caused by the drone's propellers may pull a nearby leaftowards a meshed surface located at the focal plane of the at least oneoptical probe/imaging unit. The vertical distance between the mesh andthe drone rotors is designed to enable the suction force of thedowndraft to move and essentially flatten the leaf on the meshedsurface, but not to result in strong adhesion of the leaf which couldcause unwanted drag on the lateral motion of the drone. Once the leaf iscontacted, the drone goes into hover mode and after the leaf isflattened, an image is captured by the optical channel. The leaf maythen be released, for example the drone may momentarily reduce motorspeed while performing a yaw rotation.

In some embodiments, the drone approaches a target leaf from below, andonce contact is made and the leaf is brought to the focal plane of anupwards facing imaging channel, the drone goes into hover mode, afterwhich an arm is rotated outside the mesh bringing a second imagingchannel into a focus position on the upper surface of the leaf.Optionally, an additional arm is rotated, and a frame shaped clamp isplaced onto the upper surface of the leaf prior to positioning of thesecond imaging channel.

As illustrated in FIGS. 3C1-3C2, attached to the underside of a drone204 is at least one of a downward facing imaging unit 102B1 is and anupward facing imaging unit 102B2 where the distance between the upwardand downward facing imaging units is equal to the sum of the focallengths of the imaging units. A wind blocking strip 310 is attachedbelow the drone in an area between rotors, resulting in a Bernoullieffect area. The blocking strip starts at the outer edge of the droneand ends slightly outward from the location of the imaging sensor(s). Aframe 311 is located at the level/plane in which both imaging sensors'focal areas coincide. A part of the frame forms a horizontal supportplane at the focal plane of the imaging sensor. A distance sensingelement 102C is mounted near the end of the blocking strip to providedistance information from the leaf, and an outward facing orientationimaging sensor 206 provides lateral location data of the leaf withrespect to the imaging unit to the position controller 104F. The droneflies near a target leaf 10L in a direction that brings the leaf underthe blocking strip using information from the orientation imaging sensor206 and the distance sensing element 102C. The Bernoulli effect keepsthe leaf in a relatively high position until the tip of the leaf passesout of the range of the blocking strip, whereupon, the leaf is blowndownwards by the downdraft of the rotors onto the frame at the imagingunit focal plane. The information provided by the distance sensingelement 102C is used by the position controller 104F to maintain thecorrect height of the drone in relation to the leaf. The downward draftof the drone flattens the leaf onto the frame after which images arecaptured by one or both imaging sensors.

In some embodiments, the positioning assembly includes an extension arm208 on which the optical probe is mounted. The extension arm may berotatable or extendable, e.g. having a telescopic configuration, asshown for example in FIG. 3D. As appreciated and shown in the variousfigures, the extension arm may be used when the optical probe is used asa hand-held device (FIG. 3A), or mounted on a ground vehicle (FIG. 3B)or a drone (FIGS. 3B, 3D and 3E). The extension arm may be horizontallyextending (as exemplified in FIGS. 3B and 3D) or vertically extendingdownwards or upwards (as exemplified in FIG. 3E), or incorporating ormounted on the vehicle by one or more hinges/pivots/joints 210 thatenable varying and controlling the spatial orientation of the opticalprobe with respect to the plants by varying the angle between theextension arm and the vehicle (as exemplified in FIG. 3E) and/or betweenthe extension arm and the optical probe and/or between different partsof the extension arm (as exemplified in FIG. 3B, a robotic arm). Bythis, the positioning assembly is configured and operable to facilitateimaging underside of leaves, flowers, and/or stems of fruit by theoptical probe, while minimizing damage to plant parts. In order toreduce the chance for damaging leaves or fruits of the plants, theextension arm/optical probe can contain at least one flexible joint 210,which bends if forces above a predefined level are encountered. The atleast one flexible joint may be located at various locations on theoptical probe in order to optimize the bending force required and thetime for return to normal position.

The extension arm may have a rotatable portion 208B, as exemplified inFIG. 3D, to enable rotation of the optical probe for image capture ofvarious detected objects over a wide angular range using a single set ofimaging sensor/unit, distance sensing element/unit and flash lightingelement/illuminator unit. The angular rotation rate of the optical probemay be defined to compensate for the image smearing caused by relativemotion between the target being imaged and the motion of the vehiclecarrying the optical probe. The instantaneous rotation rate is adjustedaccording to the velocity of the vehicle and the distance and angle ofthe target from the optical probe/imaging unit. The rotation directiondepends on whether the target is above or below the opticalprobe/imaging unit. A mesh casing or screen may be located around therotating portion of the optical probe, where the mesh may maintain astatic position in relation to the rotating portion or it may rotatetogether with the rotating portion.

In some embodiments, as shown in FIG. 3F, the positioning assemblyincludes a distance controlling unit 212 comprising a distancerestriction assembly 212A configured and operable to prevent the targetfrom getting closer than a minimal focal distance of the imaging unit102B. The distance controlling unit 212 may further include at least onesensing unit including at least one contact sensor 212B configured andoperable to detect at least a partial contact between the target anddistance restriction assembly 212A and generate a contact signal. Theposition controller 104F can be configured and operable to be responsiveto the contact signal from the contact sensor to initiate the imagingsession. In some embodiments, a plurality of contact sensors areprovided being associated with different parts of the distancerestriction assembly 212A. The position controller can be configured andoperable to analyze the contact signals from the contact sensors toinitiate imaging sessions using one or more respective imaging channelsof the imaging unit or using one or more imaging units.

In some embodiments, as shown in FIGS. 3G1-3G3 and FIGS. 3H1 and 3H2,the positioning assembly includes a plant shifting mechanism configuredand operable to shift location of plant parts with respect to path ofthe movement of the optical probe. In some embodiments, the plantshifting mechanism is configured and operable to shift the plant partsout of the path of movement of the optical probe. In some otherembodiments, the plant shifting mechanism is configured and operable toshift the plant parts towards the optical probe during movement andbring them into the focal range of the imaging unit.

As shown in FIG. 3G1, showing a top view of the optical probe 102, aplant shifting mechanism 214 surrounds the optical probe with a space214S therebetween, the space allows the plant shifting mechanism, atleast at a portion thereof surrounding the imaging unit, to function asthe distance controlling unit 212 described above and control a distancebetween the target and the imaging unit. A first example of the plantshifting mechanism is shown in FIG. 3G2, where the plant shiftingmechanism 214 includes a first back part 214A and a second front part214B. The back part 214A is stationary with respect to the opticalprobe, enabling the distance controlling function described above. Thefront part 214B is connected to the back part 214A via a hinge/pivot21411 and enables the front part 214B to rotate with respect to the backpart 214A. The front part 214B is moveable/switchable between at leasttwo pivotal positions, 214B1 and 214B2, with respect to the longitudinalaxis of the optical probe, and by this enables shifting plant partseither out of the way or towards the imaging unit of the optical probeas the case may be FIG. 3G3 shows a second example of the plant shiftingmechanism 214, which in this example is formed from a single part 214Cmoveable between at least two vertical positions with respect to theoptical probe and specifically with respect to the imaging unit,enabling control over the distance between the imaging unit and theimaged target, e.g. enabling bringing one plant part into focus andother plant part out of focus of the imaging unit.

As shown in FIGS. 31H1-3H2, from the side and top, the positioningassembly includes a plant shifting mechanism 214D that includes parallelslides 214D1 and 214D2 that are sloped at a leading edge of the opticalprobe and flattened at a distance from imaging channels of the imagingunit, where the distance is equal to a focal distance or less. Thisconfiguration enables stabilizing the leaf at a specific distance priorto passing over the distance sensing element and bringing differentregions of the imaged plant part, e.g. a leaf, into focus at differenttimes depending on the relative positioning between the optical probeand the plant part.

Targets, such as leaf underside, may be brought closer to the focalplane of the optical probe, for example by providing suction to flattenthe leaf on a mesh above the optical probe, by blowing air from above orby employing a dc voltage to the outside of the optical probe to createan electrostatic force to attract the leaf to the focal plane.

Reference is made to FIG. 3I illustrating another configuration of apositioning assembly configured and operable to reduce smearing andimprove image capture while there is a relative motion between theoptical probe and the plant part.

The optical probe 102 can be configured to rotate or contains arotatable optical component/element that enables rotation of the opticalaxis at the object plane about a main optical axis OA, where thedirections of the deflected optical axis rotate in a cone of directionsCoD about the main optical axis OA. This can be useful when there isrelative motion between the optical probe and plant part being imaged.The effect of the configuration described in FIG. 3I can be similar insome aspects to FIGS. 2C1 and 2C2 described above, by the ability tocontrol the path of the optical axis of the optical probe. However,because of the positioning assembly, the embodiment described in FIG. 31is effective also when the optical probe is accommodated in a one-piecehousing that can be rotated but that does not allow differentialrotation of different parts of the housing/optical probe with respect toeach other. The optical axis of the optical probe can be aligned so thatthe vector of relative motion between the object/target and the opticalprobe is tangential to the conic surface and perpendicular to theoptical axis when the optical axis is pointing to the object. Theangular rotation rate of the rotatable optical element can be set to avalue where the linear tangential velocity of the location of theoptical axis at the object plane is equal in magnitude and direction tothe vector of motion of the object relative to the optical probe. Asshown, the optical probe is mounted on a vehicle 202 that moves forwardas illustrated by the velocity vector V, typically in parallel to a rowof plants to be imaged, where a leaf 10L is exemplified and which mayhave its own spatial movement illustrated by the vector velocity V2. Theoptical probe is rotated clockwise in a circular direction, such thatits linear tangent velocity at each point on the circle is V1. Theinspection system, through the position controller 104F can define therotation velocity V1 based on the vectorial sum of the input motion dataof the vehicle (V), the plant (V2) and the rotation velocity V1, suchthat the relative velocity between the optical probe and the leaf iszero, or close to zero, whenever an image is captured.

In some embodiments, the positioning assembly may contain a rotatablemirror or a prism placed on the main optical axis outside the housing ofthe optical probe, where the optical axis is deflected by 90 degrees tothe main optical axis and where during operation an upward deflecteddirection of the optical axis is used to image the underside of leavesor fruit, a downward deflected direction of the optical axis is used toimage the top side of leaves or fruit and a sideways deflected directionof the optical axis can be used to image stems and branches of theplant.

In some embodiments, the positioning assembly is configured and operableto rotate the optical probe/element continuously in order to compensatefor image smearing during image capture by compensating for the relativemotion of the plant part and optical probe.

In some embodiments, the positioning assembly is configured and operableto rotate the optical probe/element in an oscillating motion (back andforth with respect to the path of movement of the optical probe), sothat it repeatedly scans a partial section of the conic surface, whereit attains the correct tangential velocity of the optical axisperiodically. The angular velocity of the oscillating motion may besinusoidal, sawtooth or other periodic function.

In some embodiments, the object may be imaged asynchronously, therotating optical probe/element may be held in a specific “standby”position, wherefrom when data about the relative motion between theoptical probe and the target plant part, that can be provided by thesensing unit or the orientation imaging sensor, indicates that thetarget is entering the object plane after a known distance/time, atrigger signal is generated, and the rotating probe/element performs acontrolled scanning motion. During the scanning motion, an image captureis performed, where the relative motion between the target and thestationary optical probe across the object plane is compensated by thecontrolled movement of the rotating optical probe/element.

Flash illumination may be used, in addition, to reduce the possiblesmearing during image capture. In some embodiments, illumination isprovided at the area of the cone of directions by multiple lightingelements located around the optical probe and which are individuallyoperated where the activated lighting element(s) are selected inaccordance with the angle of the deflected optical axis. In someembodiments, multiple images are captured at a specific deflection angleposition by operating different lighting elements or different subsetsof lighting elements in order to achieve different angles of obliqueillumination in each image.

Reference is made to FIGS. 4A-4B illustrating non-limiting examples ofhigh-resolution optical probes for facilitating and expediting capturingimages of plant parts, specifically leaves, in accordance with thepresent invention. As shown in FIG. 4A, the optical probe 1021 is formedwith two parts including a first part 1021X including a downward facingimaging unit 1021B1 and a second part 1021Y including an upward facingimaging unit 1021B2, where the focal areas of the imaging elementsessentially overlap, enabling imaging of both sides of a plant leaf 10Lwithout turning the plant leaf or without the need to access the topsideand the underside of the leaf sequentially. The leaf imaging opticalprobe may include a sensing unit 1021C that includes one or moredistance sensing elements for detecting distance between thecorresponding sides of the leaf and the imaging units. In the describedexample, a distance sensing element is located within each part and isconfigured to provide distance data to the corresponding imaging unit ofthe respective part. The leaf imaging optical probe 1021 also includesat least one flash illuminator unit 1021A configured and operable toilluminate the plant leaf. In some embodiments, the flash illuminatorunit is configured and operable to illuminate one side only of the leaf,typically by reflection illumination. In some embodiments, each part hasits own flash illuminator unit configured to illuminate the respectiveside of the leaf, typically by reflection illumination. In some otherembodiments, as illustrated in FIG. 4A, one flash illuminator unit islocated within the first upper part 1021X and configured and operable toilluminate the topside of the leaf by reflection illumination and theunderside of the leaf by transmission illumination. The reflection andtransmission illuminations and the imaging of the topside and undersideof the leaf may be done simultaneously or sequentially.

In some embodiments, the focal plane of the downward facing imaging unitis located laterally adjacent to the focal plane of the upward facingimaging unit and a leaf can be brought to the focal plane of a downwardfacing imaging unit sequentially to the upward facing imaging unit.

In some embodiments, the leaf imaging optical probe includes a chute1021Z configured to receive therein the plant leaf and enable theimaging of one or both sides of the plant leaf. The leaf can be drawninto the chute by suction, airflow or mechanical rollers which arelocated at the edges of the chute and out of the path to the focus area.

The leaf imaging optical probe may take a series of images as the leafslides into the chute, thus enabling covering a larger area of the leaf.The leaf imaging optical probe may include a cutter 1021T (shown forconvenience in FIG. 4B, but applicable in FIG. 4A as well) for cuttingoff the leaf from its branch, enabling performing of the imaging of theleaf while the leaf imaging optical probe is in motion to the nexttarget to be inspected. The cutting may be based on mechanical means(e.g. pulling the gripped leaf or cutting by a straight or v-shapedblade), electrical means (e.g. burning by arc) or optical means (e.g.burning by laser). The leaf may be expelled from the chute uponcompletion of the imaging. This enables increasing the time utilizationefficiency of the system by utilizing travel time between targets forperforming imaging and measurement operations.

As illustrated in FIG. 4B, in some embodiments, the leaf imaging opticalprobe is attached to a drone 204, the target leaf may be drawn in alongan angled chute until it overlaps the focal area of imaging sensors ofthe imaging units, where the downdraft of the drone, or related suction,pulls the leaf inwards along the chute until it covers the focal area.The drone may also move towards the branch holding the leaf, aiding theingress of the leaf into the chute of the leaf imaging optical probe.

As illustrated in FIGS. 4C1-4C2, in some embodiments, the leaf imagingoptical probe may include one or more of the following: a leaf holder230 for holding the leaf in a static position with respect to theimaging units, an assembly for guiding the leaf to the focal area (231A,231B), an assembly for cutting the plant branch (a branch cutter) 233and an assembly for flattening the leaf and holding it near the opticalfocal area (a leaf flattener) 232. The leaf guiding assembly may containcylindrical rolling elements (231A, 231B) on the bottom and/or top sideof the leaf enabling control of various leaf shapes of various types ofplants. The rolling elements are spaced-apart with an adjustable gap toprevent damage to the leaves. The leaf flattener 232 may be passivelypositioned or may be adjusted actively based on information about theleaf position provided by the sensing unit 1021C. The flattener islocated at the focal plan of at least one imaging unit (e.g. 1021B) andis illuminated by at least one flash illuminator unit (e.g. 1021A). Alaterally facing or forward-facing orientation imaging sensor 206 mayalso be used to recognize the position and angle of the target leaf andguide the vehicle to capture the edge of the leaf and draw it in to theopening of the leaf imaging optical probe.

As illustrated in FIGS. 4D1-4D3, the entrance to the leaf imagingoptical probe may be forward-facing (parallel) to the direction oftravel and parallel to rows of plants. Thus, the direction of leafcapture and scanning is parallel to the direction of travel. The leafimaging optical probe may include the assemblies described above withreference to FIGS. 4C1-4C2 and which are annotated with the samereference numbers. This configuration of the leaf imaging optical probeenables capturing, sampling and expelling leaves while maintainingforward motion of the vehicle. The drone 204 in FIG. 4D1 is shown as anon-limiting example of a vehicle that can also be a ground vehicle.

The leaf imaging optical probe may be designed in accordance with thespecies of plant being inspected. In this case, the customizedmechanisms are designed to match leaves of a plant according to thesize, shape, stiffness, thickness of leaves as well as leaf spacing,leaf angle and leaf location on branches. The location of the imagingsensor(s) focal area may be optimized for resolution, field of view anddepth of focus for the typical types and locations of pests and diseasesof the plant species.

The inspection system of the present invention can include an imageprocessor and analyzer, e.g. the image analyzer 104G, for processing ofthe captured images, either immediately during an imaging session orafter finishing the imaging session(s). Additionally or alternatively,the inspection system may be configured and operable to communicate withan external image processor and analyzer to send raw image data theretoand receive analyzed images aiding in planning the next imagingsessions. The image processor and analyzer can be integrated with theoptical probe or the control unit, or be located in a separate utility.The inspection system may be configured and operable to capture multipleimages with a shift in focus distance between them. The image processorand analyzer (either internal or external) detects the areas in eachimage that are in focus and merges all the in-focus areas into a singleimage. Flash illumination may be operated to reduce the motion blurringin each image during capture. The image processor and analyzer mayrefrain from utilizing one or more images out of the multiple images ifit is found, by the analysis, that the blur of the specific image islarger than a predefined threshold. Due to possible relative motionbetween the target and the optical probe, the order of focus di stancemay change, therefore the image processor and analyzer can detect theareas in focus and arrange the in-focus zones on the final imageaccordingly in a non-sequential manner. For each image used in the focusstacking, details can be recorded enabling calculation of the opticalmagnification at the focal plane, for example the distance between theback and front principle planes and their respective focal points. Theimage data is used to correct the magnification and distortion of eachimage prior to combining the images.

In some embodiments, the system is configured to utilize the relativemotion between the optical unit and the target having a certain depthprofile to generate multiple images of the target with different focusconditions covering the whole depth of the target. When approaching atarget in an essentially perpendicular direction to the target, theinspection system, specifically the position controller 104F, receivinginput position data from a sensor such as the distance sensingelement(s) or orientation image sensor, can determine distance pitchesat which the imaging unit is to be operated during motion in a multipleimage capture sequence where the axial distance pitches between theimage captures is determined in relation to the depth of focus of theimaging unit. For example, if the target has a depth Y and the imagingunit has a depth of focus of Y/n, then n in-focus images covering thedepth Y should be captured. Controlling the distances between the imagecaptures along the axial direction, being the direction of the relativemotion between the imaging unit and the target, or controlling the speedof the relative motion insures that the whole depth of the target willbe imaged. In other words, the relative position of the first and finalimages of the sequence can be defined to enable image capture of thefull depth of the object.

In some embodiments, the multiple images are not combined into a singleimage. Instead, only the in-focus objects in each image are selected andcombined onto a plane where all other areas are omitted. The resultingimage contains all objects of interest within the volume scanned duringthe multiple image capture but may contain empty areas.

The threshold for selecting an object as being in-focus may be variedand adjusted based on a learning phase. If a certain object is selectedin more than one image, a contrast comparison can be used to remove theless focused version.

In some embodiments, multiple images can be captured, each with adifferent azimuthal angle of illumination relative to the optical axisat the image plane. This can enable enhancing the contrast of smallobjects on the surface of the plant.

In the case where the object plane is not perpendicular to the opticalaxis, illuminating with an off-axis source closer to perpendicularitywith the tilted object plane can enhance the illumination uniformity,while reducing energy use of the non-operating sources. Additionally,location of the illumination lighting element relative to the opticalprobe may be adjusted to optimize the light concentration on the target.

If the required object is a fruit with shiny surface, then theillumination may be operated via a diffusive surface in order to reducebright spots from specular reflection.

The working distance of the illumination to the object plane may belarge relative to the diameter of the imaged object plane. Collimationor even reduction in the diameter of the illumination beam, may achievehigh light concentration at the object plane. In one embodiment, thelight concentration may be achieved by a cylindrical tube or conicaltube with a reflective inner surface placed around the optical axis.

The optical probe and the leaf imaging optical probe can be designed foreasy decontamination and/or replacement of parts that come into contactwith the plants. The decontamination could be performed by an additionalservice vehicle that periodically meets the vehicle during operations.Alternatively, the decontamination can be performed by the vehicleitself, for example by electrostatic charging, vibration or by heatingof surfaces.

Any part of the inspection system which may come into contact with theplants may be coated with material, such as Teflon, nano-structured orother coatings, that reduces adhesion of contamination and particles tothe surface.

In some embodiments, the optical probe can be inserted by the vehicleinto a decontamination system during flight. In a specific embodiment,the optical probe can by lowered into a downward pointing verticalposition and immersed in at least one liquid decontamination solution.

The invention claimed is:
 1. An inspection system for use in monitoringplants' conditions in a plant growing area, the inspection systemcomprising: an optical probe comprising at least one imaging set, eachimaging set comprising: a flash illuminator unit; an imaging unitconfigured with a predetermined resolution; and a sensing unit; theoptical probe being configured and operable to perform one or moreimaging sessions on targets at targets' locations along a row of plantsin a plant growing area during a movement of the optical probe along amovement path in a vicinity of the targets' locations substantiallyparallel to the raw of plants, said sensing unit comprising a distancesensing element configured and operable to determine an instantaneousdistance between the imaging unit and the target being imaged, andgenerate distance sensing data indicative thereof; and a control unitconfigured and operable to be responsive to the distance sensing data toinitiate the imaging session and synchronize operation of the flashilluminator unit and the imaging unit to capture images of the target bythe optical probe, thereby enabling analyzing the images and determininga condition of the target being indicative of at least one of pest,insect and disease presence at the target; wherein the imaging unit hasat least one of the following configurations: defines a plurality ofdifferent imaging channels having different focal conditions, or definesat least one imaging channel configured with an adaptive focal conditionwithin said focal range for imaging along said at least one imagingchannel; the imaging unit being thereby configured and operable toacquire a plurality of images with different focal conditions within thefocal range of the imaging unit, wherein the sensing unit of the opticalprobe is located at a predetermined distance before the imaging unitwith respect to the movement path of the optical probe such that thedistance sensing data is indicative of the distance between the imagingchannel and the target to be imaged; and wherein the control unitcomprises an image controller configured and operable to determine thefocal condition based on said distance sensing data and controllablyoperate the imaging unit to perform the imaging sessions with differentfocal conditions.
 2. The inspection system according to claim 1, whereinthe control unit is configured to determine a time sequence of operationof the flash illuminator unit and operation of the imaging unit with thedifferent focal conditions based on one or more of the following: thefocal conditions, the movement of the optical probe, and said distancesensing data, to thereby obtain the plurality of images.
 3. Theinspection system according to claim 1, wherein said sensing unitcomprises a one-dimensional array of distance sensing elements arrangedtransversely to the movement path of the optical probe and said imagingunit defines a two-dimensional array of the imaging channels such thateach distance sensing element is associated with a one-dimensional arrayof the imaging channels arranged in a spaced-apart relationship alongthe movement path of the optical probe.
 4. The inspection systemaccording to claim 1, wherein said sensing unit comprises a plurality ofdistance sensing elements arranged in a spaced-apart relationship on asensing surface having a predetermined geometry, each of the distancesensing elements providing distance data indicative of a distance fromsaid distance sensing element to the target location, the distancesensing data provided by the sensing unit being therefore indicative ofa plane or volume map of the vicinity of the target location dependingon the geometry of said sensing surface.
 5. The inspection systemaccording to claim 1, comprising a plant shifting mechanism configuredand operable to shift at least a part of the target with respect to themovement path of the optical probe.
 6. The inspection system accordingto claim 5, wherein said plant shifting mechanism is configured andoperable to selectively carry out at least one of the following: shiftsaid at least part of the target out of the movement path of the opticalprobe; and shift said at least part of the target towards the opticalprobe during movement and bring said plant part into the focal range ofthe imaging unit.
 7. The inspection system according to claim 5, whereinsaid plant shifting mechanism comprises parallel slides that are slopedat a leading edge of the optical probe and flattened at a distance fromthe imaging channels of the imaging unit not exceeding a focal distanceof the imaging unit.
 8. The inspection system according to claim 1,wherein said imaging unit comprises a leaf imaging optical probe.
 9. Theinspection system according to claim 8, wherein the leaf imaging opticalprobe comprises a downward facing imaging element and an upward facingimaging element, whereby fields of view of the imaging elements areoverlapping, enabling imaging of both sides of a plant leaf withoutturning the plant leaf.
 10. The inspection system according to claim 8,wherein the leaf imaging optical probe comprises at least one flashilluminator element configured and operable to illuminate both sides ofthe plant leaf, and wherein reflected light imaging is performed on oneside of the leaf either simultaneously or sequentially with transmittedlight imaging on an opposite side of the leaf.
 11. The inspection systemaccording to claim 1, wherein the control unit is configured andoperable to utilize data indicative of velocity of said movement alongthe movement path and determine a time passing between time of detectionof the target by the sensing unit and the time at which the imagingsession is to be initiated to thereby timely activate the flashilluminator unit and the imaging unit.
 12. The inspection systemaccording to claim 1, wherein the control unit is configured andoperable to spatially divide the target into one or more sections andallocate one or more imaging channels for imaging each of said one ormore sections.
 13. The inspection system according to claim 12, whereinthe control unit is configured and operable to allocate said one or moreimaging channels for imaging each of said one or more sections such thatfields of view of the imaging channels in each section either overlap orare shifted along the movement path of the optical probe, the pluralityof images thereby covering the whole target.
 14. The inspection systemaccording to claim 1, wherein said flash illuminator unit comprises oneor more lighting elements associated with each of the imaging channels,each of said one or more lighting elements being arranged with adifferent angular orientation with respect to an optical axis of therespective imaging channel, said control unit being configured andoperable to determine an angle between the target location and theoptical axis of the imaging channel, and select, for each imagingsession, one or more of said one or more lighting elements to provideuniform illumination of the target.
 15. The inspection system accordingto claim 1, wherein said control unit further comprises a flashcontroller configured and operable to control at least one ofillumination intensity, illumination angle and illumination time patternof said flash illuminator unit, based on one or more of the following:input motion data indicative of the movement path of the optical probein the vicinity of the target location, number of lighting elements ofthe flash illuminator unit, distance of a focal plane, exposure time,ambient light, an angle between the target and the flash illuminatorunit, reflectivity of target, type of the target, and type of a part ofthe target being imaged.
 16. The inspection system according to claim15, further comprising a movement detection unit configured and operablefor providing input motion data to control the imaging sessions and atime sequence of operation of the flash illuminator unit and of thedifferent imaging channels.
 17. The inspection system according to claim1, further comprising one or more of the following: an indication unitconfigured and operable to provide indication about an operational stateof the optical probe; a position controller configured and operable tocontrol one or more of the following: a position of the optical probe,an orientation of the optical probe, an orientation of the movement pathof the optical probe with respect to said target location, based oninput position data; at least one additional imaging unit configured fordefining one or more measurement channels, for performing at least oneof spectrophotometry, multi-spectral and UV-fluorescence measurements; adistance controlling unit comprising a distance restriction assemblyconfigured and operable to prevent the target from getting closer than aminimal focal distance of the imaging unit; a positioning assemblyconfigured and operable to control the movement path of the opticalprobe in the vicinity of the target and adjust a position of the opticalprobe with respect to said target location, to enable one or more of thefollowing: imaging underside, upper side or side of a plant part by theimaging unit, and reduce image smearing and blur during relative motionbetween the optical probe and the target; and an image analyzerconfigured and operable to carry out at least one of the following:detect in-focus portions in each of a plurality of images acquired bythe imaging unit and merge the in-focus portions into a single in-focusimage of the target; detect optimally-illuminated portions in theplurality of images, being acquired with different imaging conditionsincluding at least one of an illumination intensity and illuminationangle, and merge the optimally illuminated portions into a single imageof the target.
 18. The inspection system according to claim 1, furthercomprising a position controller configured and operable to control oneor more of the following: a position of the optical probe, anorientation of the optical probe, an orientation of the movement path ofthe optical probe with respect to said target location, based on inputposition data; the position controller being configured and operable tocarry out at least one of the following: to communicate with an externalinformation source to receive said input position data; and to accesssaid input position data stored in a database of an inspection history.19. The inspection system according to claim 18, wherein the opticalprobe is configured and operable to perform said one or more imagingsessions on the target having a certain depth profile, said imaging unithaving a certain depth of focus smaller than a depth of the target, andsaid position controller being configured and operable to determine apitch distance, along the movement path, between consecutive pluralityof images being acquired by the imaging unit, and control the motion andimage acquisition of the imaging unit to capture the plurality of imagessuch that each image is acquired at a different location along the depthprofile of the target, thereby enabling generating focused images of thetarget along the whole depth of the target.
 20. The inspection systemaccording to claim 1, comprising a positioning assembly comprising anorientation imaging sensor configured and operable to provide path dataindicative of one or more obstacles or target parts located in themovement path of the optical probe, said control unit being configuredand operable to receive and analyze said path data, and selectivelycarry out at least one of the following: selecting the target to beimaged; upon identifying the target parts in the path data, control themovement path of the optical probe in order to bring the target partsinto the focal range of the imaging unit; and upon identifying one ormore of the obstacles in the path data control the movement path of theoptical probe in order to prevent collision of the optical probe withthe obstacles.
 21. The inspection system according to claim 1,configured as a hand-held device, wherein said hand-held device has oneof the following configurations: (i) the hand-held device comprises acommon housing carrying said optical probe and said control unit; and(ii) the hand-held device is configured as a two-part unit carrying theoptical probe and the control unit in respective first and second unitparts configured to be connected to one another.
 22. A vehicle carryingthe inspection system of claim 1, said vehicle being configured as aground vehicle or as a flying platform.
 23. An inspection system for usein monitoring plants' conditions in a plant growing area, the inspectionsystem comprising: an optical probe comprising at least one imaging set,each imaging set comprising: a flash illuminator unit; an imaging unitconfigured with a predetermined resolution; and a sensing unit; theoptical probe being configured and operable to perform one or moreimaging sessions on targets at targets' locations along a row of plantsin a plant growing area during a movement of the optical probe along amovement path in a vicinity of the targets' locations substantiallyparallel to the raw of plants, said sensing unit comprising a distancesensing element configured and operable to determine an instantaneousdistance between the imaging unit and the target being imaged, andgenerate distance sensing data indicative thereof; and a control unitconfigured and operable to be responsive to the distance sensing data toinitiate the imaging session and synchronize operation of the flashilluminator unit and the imaging unit to capture images of the target bythe optical probe, thereby enabling analyzing the images and determininga condition of the target being indicative of at least one of pest,insect and disease presence at the target; wherein the imaging unitdefines a plurality of different imaging channels having different focalconditions; the imaging unit being thereby configured and operable toacquire a plurality of images with different focal conditions within afocal range of the imaging unit, wherein the sensing unit of the opticalprobe is located at a predetermined distance before the imaging unitwith respect to the movement path of the optical probe such that thedistance sensing data is indicative of the distance between the imagingchannel and the target to be imaged; and wherein the control unitcomprises an image controller configured and operable to determine thefocal condition based on said distance sensing data and controllablyoperate the imaging unit to perform the imaging sessions with differentfocal conditions, the control unit being configured to determine a timesequence of operation of the flash illuminator unit and operation of theimaging unit with the different focal conditions based on one or more ofthe following: the focal conditions, the movement of the optical probe,and said distance sensing data, to thereby obtain the plurality ofimages.